Pulse Oximetry Con: Stop Living in the Cave

Pulse oximetry is a clinical monitoring tool that commonly serves as a biomarker for hypoxia. It is a simple, practical, noninvasive tool so deeply embedded in medicine that it is typically the first interaction a patient has with a monitoring technology. It is such an integral part of vital signs measurement in critical care that any argument questioning its efficacy or safety is ridiculed and treated as heresy. However, as described by Plato, we have been living in a cave where we are the prisoners of a false reality of the infallibility of this medical technology, like shadows cast upon the cave wall by firelight. The cave is all most of us know, and few are willing to venture out of the cave into the sunlight; the rest remaining inside considering the truth not worth seeking. Like any instrument we use in our critical care cave, pulse oximetry has become such a part of our daily existence that we may have neglected to see that both the tool itself, and our use of it may be fraught with fallacies and represent a “false reality.” As a profession, we need to venture out of the cave and reconsider the accuracy and value of pulse oximetry and respond appropriately. Pulse oximetry has several limitations. No perfect tool exists, and any tool is only as good as the operator’s understanding of its perils and pitfalls in using it effectively. We describe the current state of science as it relates to the limitations of pulse oximetry, with the hope that this will become a trigger for igniting further research into improving its use.